Broadway box office continued to pick up last week, with “Follies” becoming one of the rare Stephen Sondheim tuners to crack the $1 million mark and one-act play anthology “Relatively Speaking” bowing strong in its first frame of previews.Rising in the wake of enthusiastic reviews, “Follies” ($1,122,778) climbed a whopping $245,000 to join the millionaires club, a feat few of Sondheim’s cerebral musicals manage to accomplish. The only other one to do so was “A Little Night Music” a couple of seasons ago, fueled by topliners Catherine Zeta-Jones and Angela Lansbury. “Follies” joined a six-member millionaires club in a week that saw “The Book of Mormon” ($1,293,272) again beat out “Spider-Man: Turn Off the Dark” ($1,269,403) in a venue that’s significantly smaller than the Foxwoods, where “Spider-Man” plays. “Relatively” ($716,252) — the triple-bill of comedies by Woody Allen, Elaine May and Ethan Coen — averaged houses filled to 98% over its first eight previews. That’s a solid showing for a play whose scribes are seemingly well-known enough to provide a jolt of marquee appeal. Another addition, “The Mountaintop” ($411,044 for five previews), also joined the fray and added coin to the Rialto pot. The two-hander, which can turn heads with stars Samuel L. Jackson and Angela Bassett, reported auds that averaged about 87% of capacity. Nearly every show on the boards upticked last week, some significantly so: “The Phantom of the Opera” ($833,171), “Mamma Mia!” ($825,127) and “Memphis” ($775,877) each rose by $125,000 or more. Two shows from the spring that never performed as well as expected over the summer, “Priscilla Queen of the Desert” ($798,122) and “Sister Act” ($721,976), also stepped up as each continued to find a foothold with ticketbuyers. Broadway cume climbed an impressive $2.5 million to $18.5 million for 22 shows running, while overall attendance climbed by more than 25,000 to 206,595, hitting 88% of capacity. That attendance is about on par with last season at this time, although with 28 shows running at the time, it came to only 81% of the sesh’s capacity. In the coming frames, box office looks likely to climb as further additions are made to the slate, although Rosh Hashanah is poised to siphon off some sales later this week.